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What is bleed in printing?
Bleed is the part of an image printed beyond the cut line so that no unprinted edge remains after trimming. PrintSimple gives 3 mm each side and a 4 mm safety margin inside the trim; Wikipedia gives 1/8 inch, or roughly 2 to 5 mm depending on the printer.
Diagram: bleed, trim and safe zone. Schematic, not to scale.
Three zones
| Zone | Meaning | Figure |
|---|---|---|
| Bleed | Image and background run past the cut so no white edge shows if paper shifts | 3 mm each side (PSB); 1/8 inch (WBL); roughly 2 to 5 mm depending on printer (WBL); 0.25 inch for large-format posters (WBL) |
| Trim | The cut line where the finished product is cut | Final size |
| Safety margin and safe zone | Distance inside the trim; keep text and key images inside | 4 mm, measured from the final trimmed size (PSB) |
File size worked out
File size = trimmed size + 2 x bleed (3 mm). Safe area = trimmed size minus 2 x safety margin (4 mm). Examples:
| Item | Trimmed size | File size with 3 mm bleed | Safe area (4 mm margin) |
|---|---|---|---|
| A4 trimmed size (mm) | 210 x 297 | 216 x 303 | 202 x 289 |
| 8 x 10 in trimmed size (mm) | 203.2 x 254 | 209.2 x 260 | 195.2 x 246 |
Wikipedia explains the reason: it is very hard to print exactly to the edge of a sheet, so a larger area is printed and trimmed. Printers differ, so confirm the bleed with whoever prints your file. 1/8 inch is 3.175 mm.
Sources
- PrintSimple: what are bleed, safety margin and safe zone (fetched 2026-11-12)
- Wikipedia: Bleed (printing) (fetched 2026-11-12)
Figures from these pages are paraphrased and re-checked on 2026-11-12. Where two sources disagree, both figures are shown. Hardware and wall products vary, so follow the pack instructions.